Good morning, Fred.
If I could add a further note of caution, by adding lights or even just changing the existing lights, you can significantly affect the performance of Ship Simulator.
If, as a result, you find that you have jerky movement (in the game, not yourself!) or bits of ships are missing or other odd effects, then you've messed it up.
In that case, replace the files or in extreme cases, reinstall the game, following the directions in my flow chart (Technical Support area).